Why does my engine rattle so much
 

Could someone let me know why does my E250 shake so much when i switch into gear. My father inlaw said that when the van was in his possesion his mechanic told him that one of the fuel injectors was bad along with the motor mounts and motor oil leak. There was once a time when he overheated the van and now theres water in the engine. What should i do. The engine runs strong in my opinion but the motor oil leak and the engine rattle bugs me. I am going to stick with 4.9 300 Line 6 engine because this forums has explained that it's a far superior engine than the V8. But now my question is should i rebuild the original engine in the van now or swap it out for a rebuilt one. I have asked around and am being charged more for the rebuilding of the original engine than a swap for a rebuilt one. The prices i got are

$1,600-----Original engine rebuilding
$1,000-----Rebuilt core exchange

I really need help guys because i plan on keeping this van for a pretty long time and would like to make wise decisions. Thanks in advance

RE: Why does my engine rattle so much
 

If by water in Engine you mean in the oil then this is an impending problem IMO, Just swap to rebuilt engine it will surely come with more warranty than anyone will give you for rebuilding your current one. BTW either of those prices seem extremely low, is that with you pulling the current engine out?

RE: Why does my engine rattle so much
 

Yes it is the current engine in the van now.why does the van settle down sometimes making me think the engine turned off. Whai mean by this is that the engine is so calm that it make me think the van turned off but when i give it gas it revs up. what could be causing this.Thanks